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<FONT color="green">001</FONT>    // Copyright (c) 2011, Mike Samuel<a name="line.1"></a>
<FONT color="green">002</FONT>    // All rights reserved.<a name="line.2"></a>
<FONT color="green">003</FONT>    //<a name="line.3"></a>
<FONT color="green">004</FONT>    // Redistribution and use in source and binary forms, with or without<a name="line.4"></a>
<FONT color="green">005</FONT>    // modification, are permitted provided that the following conditions<a name="line.5"></a>
<FONT color="green">006</FONT>    // are met:<a name="line.6"></a>
<FONT color="green">007</FONT>    //<a name="line.7"></a>
<FONT color="green">008</FONT>    // Redistributions of source code must retain the above copyright<a name="line.8"></a>
<FONT color="green">009</FONT>    // notice, this list of conditions and the following disclaimer.<a name="line.9"></a>
<FONT color="green">010</FONT>    // Redistributions in binary form must reproduce the above copyright<a name="line.10"></a>
<FONT color="green">011</FONT>    // notice, this list of conditions and the following disclaimer in the<a name="line.11"></a>
<FONT color="green">012</FONT>    // documentation and/or other materials provided with the distribution.<a name="line.12"></a>
<FONT color="green">013</FONT>    // Neither the name of the OWASP nor the names of its contributors may<a name="line.13"></a>
<FONT color="green">014</FONT>    // be used to endorse or promote products derived from this software<a name="line.14"></a>
<FONT color="green">015</FONT>    // without specific prior written permission.<a name="line.15"></a>
<FONT color="green">016</FONT>    // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS<a name="line.16"></a>
<FONT color="green">017</FONT>    // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT<a name="line.17"></a>
<FONT color="green">018</FONT>    // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS<a name="line.18"></a>
<FONT color="green">019</FONT>    // FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE<a name="line.19"></a>
<FONT color="green">020</FONT>    // COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,<a name="line.20"></a>
<FONT color="green">021</FONT>    // INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,<a name="line.21"></a>
<FONT color="green">022</FONT>    // BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;<a name="line.22"></a>
<FONT color="green">023</FONT>    // LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER<a name="line.23"></a>
<FONT color="green">024</FONT>    // CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT<a name="line.24"></a>
<FONT color="green">025</FONT>    // LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN<a name="line.25"></a>
<FONT color="green">026</FONT>    // ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE<a name="line.26"></a>
<FONT color="green">027</FONT>    // POSSIBILITY OF SUCH DAMAGE.<a name="line.27"></a>
<FONT color="green">028</FONT>    <a name="line.28"></a>
<FONT color="green">029</FONT>    package org.owasp.html;<a name="line.29"></a>
<FONT color="green">030</FONT>    <a name="line.30"></a>
<FONT color="green">031</FONT>    import java.util.List;<a name="line.31"></a>
<FONT color="green">032</FONT>    <a name="line.32"></a>
<FONT color="green">033</FONT>    import javax.annotation.Nullable;<a name="line.33"></a>
<FONT color="green">034</FONT>    import javax.annotation.concurrent.Immutable;<a name="line.34"></a>
<FONT color="green">035</FONT>    <a name="line.35"></a>
<FONT color="green">036</FONT>    /**<a name="line.36"></a>
<FONT color="green">037</FONT>     * A policy that can be applied to an element to decide whether or not to<a name="line.37"></a>
<FONT color="green">038</FONT>     * allow it in the output, possibly after transforming attributes.<a name="line.38"></a>
<FONT color="green">039</FONT>     * &lt;p&gt;<a name="line.39"></a>
<FONT color="green">040</FONT>     * Element policies are applied &lt;strong&gt;after&lt;/strong&gt;<a name="line.40"></a>
<FONT color="green">041</FONT>     * {@link AttributePolicy attribute policies} so<a name="line.41"></a>
<FONT color="green">042</FONT>     * they can be used to add extra attributes.<a name="line.42"></a>
<FONT color="green">043</FONT>     *<a name="line.43"></a>
<FONT color="green">044</FONT>     * @author Mike Samuel &lt;mikesamuel@gmail.com&gt;<a name="line.44"></a>
<FONT color="green">045</FONT>     * @see HtmlPolicyBuilder#allowElements(ElementPolicy, String...)<a name="line.45"></a>
<FONT color="green">046</FONT>     */<a name="line.46"></a>
<FONT color="green">047</FONT>    @TCB public interface ElementPolicy {<a name="line.47"></a>
<FONT color="green">048</FONT>      /**<a name="line.48"></a>
<FONT color="green">049</FONT>       * @param elementName the lower-case element name.<a name="line.49"></a>
<FONT color="green">050</FONT>       * @param attrs a list of alternating attribute names and values.<a name="line.50"></a>
<FONT color="green">051</FONT>       *    The list may be added to or removed from.  When removing, be<a name="line.51"></a>
<FONT color="green">052</FONT>       *    careful to remove both the name and its associated value.<a name="line.52"></a>
<FONT color="green">053</FONT>       *<a name="line.53"></a>
<FONT color="green">054</FONT>       * @return {@code null} to disallow the element, or the adjusted element name.<a name="line.54"></a>
<FONT color="green">055</FONT>       */<a name="line.55"></a>
<FONT color="green">056</FONT>      public @Nullable String apply(String elementName, List&lt;String&gt; attrs);<a name="line.56"></a>
<FONT color="green">057</FONT>    <a name="line.57"></a>
<FONT color="green">058</FONT>    <a name="line.58"></a>
<FONT color="green">059</FONT>      /** Utilities for working with element policies. */<a name="line.59"></a>
<FONT color="green">060</FONT>      public static final class Util {<a name="line.60"></a>
<FONT color="green">061</FONT>        private Util() { /* uninstantiable */ }<a name="line.61"></a>
<FONT color="green">062</FONT>    <a name="line.62"></a>
<FONT color="green">063</FONT>        /**<a name="line.63"></a>
<FONT color="green">064</FONT>         * Given zero or more element policies, returns an element policy equivalent<a name="line.64"></a>
<FONT color="green">065</FONT>         * to applying them in order failing early if any of them fails.<a name="line.65"></a>
<FONT color="green">066</FONT>         */<a name="line.66"></a>
<FONT color="green">067</FONT>        public static final ElementPolicy join(ElementPolicy... policies) {<a name="line.67"></a>
<FONT color="green">068</FONT>    <a name="line.68"></a>
<FONT color="green">069</FONT>          class PolicyJoiner {<a name="line.69"></a>
<FONT color="green">070</FONT>            ElementPolicy last = null;<a name="line.70"></a>
<FONT color="green">071</FONT>            ElementPolicy out = null;<a name="line.71"></a>
<FONT color="green">072</FONT>    <a name="line.72"></a>
<FONT color="green">073</FONT>            void join(ElementPolicy p) {<a name="line.73"></a>
<FONT color="green">074</FONT>              if (p == REJECT_ALL_ELEMENT_POLICY) {<a name="line.74"></a>
<FONT color="green">075</FONT>                out = p;<a name="line.75"></a>
<FONT color="green">076</FONT>              } else if (out != REJECT_ALL_ELEMENT_POLICY) {<a name="line.76"></a>
<FONT color="green">077</FONT>                if (p instanceof JoinedElementPolicy) {<a name="line.77"></a>
<FONT color="green">078</FONT>                  JoinedElementPolicy jep = (JoinedElementPolicy) p;<a name="line.78"></a>
<FONT color="green">079</FONT>                  join(jep.first);<a name="line.79"></a>
<FONT color="green">080</FONT>                  join(jep.second);<a name="line.80"></a>
<FONT color="green">081</FONT>                } else if (p != last) {<a name="line.81"></a>
<FONT color="green">082</FONT>                  last = p;<a name="line.82"></a>
<FONT color="green">083</FONT>                  if (out == null || out == IDENTITY_ELEMENT_POLICY) {<a name="line.83"></a>
<FONT color="green">084</FONT>                    out = p;<a name="line.84"></a>
<FONT color="green">085</FONT>                  } else if (p != IDENTITY_ELEMENT_POLICY) {<a name="line.85"></a>
<FONT color="green">086</FONT>                    out = new JoinedElementPolicy(out, p);<a name="line.86"></a>
<FONT color="green">087</FONT>                  }<a name="line.87"></a>
<FONT color="green">088</FONT>                }<a name="line.88"></a>
<FONT color="green">089</FONT>              }<a name="line.89"></a>
<FONT color="green">090</FONT>            }<a name="line.90"></a>
<FONT color="green">091</FONT>          }<a name="line.91"></a>
<FONT color="green">092</FONT>    <a name="line.92"></a>
<FONT color="green">093</FONT>          PolicyJoiner pu = new PolicyJoiner();<a name="line.93"></a>
<FONT color="green">094</FONT>          for (ElementPolicy policy : policies) {<a name="line.94"></a>
<FONT color="green">095</FONT>            if (policy == null) { continue; }<a name="line.95"></a>
<FONT color="green">096</FONT>            pu.join(policy);<a name="line.96"></a>
<FONT color="green">097</FONT>          }<a name="line.97"></a>
<FONT color="green">098</FONT>          return pu.out != null ? pu.out : IDENTITY_ELEMENT_POLICY;<a name="line.98"></a>
<FONT color="green">099</FONT>        }<a name="line.99"></a>
<FONT color="green">100</FONT>    <a name="line.100"></a>
<FONT color="green">101</FONT>      }<a name="line.101"></a>
<FONT color="green">102</FONT>    <a name="line.102"></a>
<FONT color="green">103</FONT>      public static final ElementPolicy IDENTITY_ELEMENT_POLICY<a name="line.103"></a>
<FONT color="green">104</FONT>          = new ElementPolicy() {<a name="line.104"></a>
<FONT color="green">105</FONT>        public String apply(String elementName, List&lt;String&gt; attrs) {<a name="line.105"></a>
<FONT color="green">106</FONT>          return elementName;<a name="line.106"></a>
<FONT color="green">107</FONT>        }<a name="line.107"></a>
<FONT color="green">108</FONT>      };<a name="line.108"></a>
<FONT color="green">109</FONT>    <a name="line.109"></a>
<FONT color="green">110</FONT>      public static final ElementPolicy REJECT_ALL_ELEMENT_POLICY<a name="line.110"></a>
<FONT color="green">111</FONT>          = new ElementPolicy() {<a name="line.111"></a>
<FONT color="green">112</FONT>        public @Nullable String apply(String elementName, List&lt;String&gt; attrs) {<a name="line.112"></a>
<FONT color="green">113</FONT>          return null;<a name="line.113"></a>
<FONT color="green">114</FONT>        }<a name="line.114"></a>
<FONT color="green">115</FONT>      };<a name="line.115"></a>
<FONT color="green">116</FONT>    <a name="line.116"></a>
<FONT color="green">117</FONT>    }<a name="line.117"></a>
<FONT color="green">118</FONT>    <a name="line.118"></a>
<FONT color="green">119</FONT>    @Immutable<a name="line.119"></a>
<FONT color="green">120</FONT>    final class JoinedElementPolicy implements ElementPolicy {<a name="line.120"></a>
<FONT color="green">121</FONT>      final ElementPolicy first, second;<a name="line.121"></a>
<FONT color="green">122</FONT>    <a name="line.122"></a>
<FONT color="green">123</FONT>      JoinedElementPolicy(ElementPolicy first, ElementPolicy second) {<a name="line.123"></a>
<FONT color="green">124</FONT>        this.first = first;<a name="line.124"></a>
<FONT color="green">125</FONT>        this.second = second;<a name="line.125"></a>
<FONT color="green">126</FONT>      }<a name="line.126"></a>
<FONT color="green">127</FONT>    <a name="line.127"></a>
<FONT color="green">128</FONT>      public @Nullable String apply(String elementName, List&lt;String&gt; attrs) {<a name="line.128"></a>
<FONT color="green">129</FONT>        elementName = first.apply(elementName, attrs);<a name="line.129"></a>
<FONT color="green">130</FONT>        return elementName != null ? second.apply(elementName, attrs) : null;<a name="line.130"></a>
<FONT color="green">131</FONT>      }<a name="line.131"></a>
<FONT color="green">132</FONT>    }<a name="line.132"></a>




























































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